Biography: Mary Marg Helgenberger (pronounced Mar-guh with a hard 'G', unlike the name Marge) born November 16, 1958), is an American actress.

Helgenberger was born in Fremont, Nebraska to Hugh and Kay Helgenberger.

A scout for the soap opera Ryan's Hope discovered Helgenberger when she performed as Kate in a Northwestern University production of William Shakespeare's The Taming of the Shrew, in the summer of 1981. Helgenberger debuted on the series in March 1982 playing Siobhan Ryan Novak, until 1986. Although she was actually the third actress to play the role, she is the one most identified with the part.

In 1984, Helgenberger met Alan Rosenberg, a guest actor on Ryan's Hope. The two became friends and started dating in 1986. They married in 1989 and have one son, Hughie, named after Marg's father, Hugh Helgenberger.

Her first famous television role was on the period drama China Beach. Helgenberger won an Emmy for the role (Supporting Actress).

She later won critical acclaim for her portrayal of Patsy Ramsey. She is probably now best known as her current portral of Catherine Willows in the television series CSI: Crime Scene Investigation.